1. Field
The present disclosure relates generally to an improved data processing system in particular to a method and apparatus for measuring positions on objects. Still more particularly, the present disclosure relates to a computer implemented method, apparatus, and computer program code for identifying location information about objects.
2. Background
Aircraft maintenance technicians conduct routine maintenance as well as replace parts and repair surfaces of aircraft. Maintenance may involve structures in which inspections for corrosion, cracks, or distortion is made. These tasks may be performed inside and outside of various aircraft structures, such as the fuselage, wings, landing gear, or other structures. These different inspections require identifying precise locations.
For example, when a damaged area on an aircraft is identified, location information may be used along with models of the aircraft to identify components that may be affected using a three-dimensional model of the aircraft. Without location information that is precise enough to identify items that may be damaged, a physical inspection of the aircraft is required to identify these potential items. An aircraft maintenance technician may identify the damaged area and then count the number of frames from that location to one end of the aircraft to identify the position in the aircraft. This type of procedure is time consuming as well as potentially inaccurate. Further, the accuracy of the identification may not be as high as desired for identifying potentially affected components.
For example, an aircraft may have skin sections measured in inches in which each skin section has a specific structure that may be different from other surrounding skin sections. Precise location information becomes critical in performing repairs on these and other types of aircraft parts.
Currently used processes for gathering information on an aircraft uses a station line, a butt line, and a water line to identify locations of components. The station line is the X axis of a system. This line is positive pointing towards the aft part of the aircraft and typically begins somewhere before the nose of the fuselage. The butt line is the Y axis of the aircraft. This axis is positive pointing along the aircraft's left wing. The water line is the Z axis of the aircraft. This axis points upward. This type of location information is used with three-dimensional models of the aircraft to identify components and information about components in the area where damage may be identified. This type of information also may be used to identify locations for maintenance or locations where other inspections may be performed.
Measurement of location information on a large object, such as an aircraft, is a difficult process with currently used techniques. These techniques require fixed positions for the measurement equipment. One technique for measuring location information utilizes a theodolite, which is an optical instrument that measures both horizontal and vertical angles. This instrument typically consists of a small mounted telescope that is rotatable in both horizontal and vertical planes. The use of this type of instrument is limited because the instrument requires a fixed location to perform measurements.
Another technique used to measure objects involves photogrammetry. The technique is a remote sensing technology in which geometric properties about the objects are identified from photographic images. This technique may identify three-dimensional coordinates for points on an object based on measurements made in two or more photographic images taken from different positions.
Yet another technique that may be used to identify location information on objects utilizes lasers. Currently, the use of lasers also requires fixed position measurement equipment. Additionally, these different techniques also have high costs relative to the accuracy desired in identifying location information.
The currently available measurement techniques are capable of providing measurements with the tolerances needed for aircraft. These systems, however, are limited by these measuring instruments being in fixed locations.
With the use of fixed positions, the fixed position from a measurement is taken in a known location that is not in motion. This type of requirement increases the cost and time needed to identify locations. In identifying coordinates for a three-dimensional coordinate system, these coordinates may be located using an estimation from fixed hard points and locations on the aircraft. These types of guesses may produce errors in the process of determining an exact location. The currently used techniques provide adequate results when a sufficient representation of the object being searched exists. These techniques, however, still may not provide the needed precision in large areas, very small areas, or areas in which modifications have occurred.
Therefore, it would be advantageous to have a method and apparatus that overcomes the above described problems.